Synthesis and Pyrolysis-Field Ionization Mass Spectrometric Study of an Aromatic Polyamide Having Azo Group in the Main Chain

The reductive coupling of p-nitrobenzoic acid with glucose solution gave 4,4′-azodibenzoic acid and was converted to 4,4′-azodibenzoylchloride using thionyl chloride. This aromatic diacid chloride was condensed with 4,4′-Diaminodiphenyl ether by two different techniques to yield aromatic polyamide. The low temperature polymerization method resulted in comparatively high molecular weight polymer as evidenced by intrinsic viscosity values. The structure of the material was confirmed by IR studies. Detailed pyrolysis-field ionization mass spectral studies carried out indicated two major degradations. In the temperature region (180–200°C), the mass spectrum showed intense peaks at m/z = 166 and 149 which can be explained from the fragmentation of azodicarboxylic acid formed from the polymer. The mass spectrum recorded at 465°C gave clear proof for the structure of the polyamide and also enough evidence was noted for the hydrogenation of the azo group during pyrolysis.